Addressing a key purpose of the NICHD P01 to encourage multidisciplinary approaches to the investigation of complex problems relevant to NICHD's mission-our program project's principal goal is to understand why human capital intervention programs and policies, directed at children in the preschool, middle childhood and adolescent stages of development, have the effects, non-effects and, in some cases, perverse effects that they do. Our common conceptual approach views the extent to which children and youth profit from interventions as depending on the congruence ("fit") between the developmental needs of children and youth and the design of the intervention policies. The specific policy interventions we investigate include: i) early childhood programs such as Head Start and Early Head Start (Project I);ii) state standards for health education curricula involving alcohol, tobacco and other drugs (Project II);and iii) school voucher programs and state policies regarding high-stakes exams for grade promotion and/or graduation (Project III). A fourth project (IV) complements the first three by addressing the "So what?" question of the possible adult consequences of augmenting skills or improving behavior at various points in childhood and adolescence. Where possible, our policy-analytic methods take advantage of random assignment or natural experimental methodologies. To address policy research questions regarding the distribution of policy impacts, we propose to develop new analytic methods. We will also seek to "get inside the black box" to identify particular intervention elements that may be contributing to the observed program effects on preschoolers and school- aged children and youth in anticipation of future program design and evaluation. Our collaboration involves economists, developmental psychologists, sociologists and epidemiologists based mainly at the University of California, Irvine. A single, Administrative Core, provides administrative support for all projects monitors the progress of each project and facilitates the dissemination of the results of the research to the broader research community and the policy world. Taken together, the group's involvement with multiple projects as well as seminars, jointly-authored papers and other core activities will constitute a research network - the Irvine Network on Interventions in Development. PUBLIC HEALTH RELEVANCE: The path to our nation's future prosperity and security rests on its ability to promote human capital skills, broadly conceived, among its children and youth. Our program project draws on the expertise and close collaboration of economists, developmental psychologists, sociologists and epidemiologists to understand the impacts of educational interventions designed to augment human capital and promote positive behavior, particularly for children and youth raised in economically disadvantaged families.